This invention relates, in general, to voltage controlled oscillators, and more specifically, to wide band voltage controlled oscillators used in monolithic microwave integrated circuits (MMIC).
Oscillators used in MMIC circuits have used inductors and varactor capacitors to achieve wide band widths. The use of varactors has required external tuning elements, as well as multiple tuning elements. Multiple tuning elements have inherent problems such as switching transients. The low Q nature of varactor diodes also limits the performance of the MMIC circuit. Use of inductors require MMIC's to be proportionately large. Inherent with the use of inductors is low yield, lower frequencies obtainable and proportionately large inductor size. Given the external, multiple tuning elements and the proportionately large inductors, use of MMIC wideband voltage controlled oscillators (WBVCO) has been somewhat limited. If WBVCO's could be reduced in size and entirely incorporated on a single chip with higher yields and broader frequency ranges, MMIC WBVCO's could be used in many new applications.